In a vehicle at which an internal combustion engine is mounted, generally, the heat generated during the operation of the engine is transmitted to cylinder heads, pistons and valves, and accordingly, if the temperatures of the components are excessively raised, thermal expansion or degradation occurs to decrease the strength of the components, reduce the life span of the engine, make a bad combustion state to cause knocking or pre-ignition, and decrease the output of the engine.
In case where the engine is incompletely cooled, further, an oil film on the inner peripheral surface of a cylinder is cut to cause a bad lubricating function, and in addition, engine oil is deformed in quality to cause irregular abrasion of the cylinder. Furthermore, the piston may be fused to the inner peripheral surface of the cylinder.
In addition to the engine of the vehicle, on the other hand, the electric parts of the vehicle, such as motors, inverters, and battery stacks should be cooled, but since the cooling water passing through the engine and the cooling water passing through the electric parts have a given temperature difference therebetween, the vehicle cannot have a single cooling system.
FIGS. 1A and 1B are block diagrams showing conventional cooling systems for a vehicle, wherein FIG. 1A shows the cooling system for an engine, and FIG. 1B shows the cooling system for electric parts.
In more detail, an engine cooling system 10 includes a water pump 15 adapted to circulate cooling water for cooling an engine 1, a first radiator 11 for cooling the cooling water, a first cooling water storage tank 13 for supplying the cooling water to the first radiator 11, and a first cooling water adjusting cap 12.
According to the engine cooling system 10, at this time, the first radiator 11, the water pump 15 and the engine 1 are connected to each other through a first connection line 14.
Further, an electric part cooling system 20 includes a water pump 25 adapted to circulate cooling water for cooling electric parts 2, a second radiator 21 for cooling the cooling water, a second cooling water storage tank 23 for supplying the cooling water to the second radiator 21, and a second cooling water adjusting cap 22.
At this time, the electric parts 2 of the electric part cooling system 20 include an inverter and a generator used also as a starter.
According to the electric part cooling system 20, in the same manner as the engine cooling system 10, the second radiator 21, the water pump 25 and the electric parts 2 are connected to each other through a second connection line 24.
At this time, the first radiator 11 and the second radiator 21 constitute a cooling module, together with a condenser and a fan and shroud assembly, and the cooling water is heat-exchanged with vehicle wind and the air introduced through the fan and shroud assembly.
FIG. 2 shows one example of conventional cooling modules.
According to a cooling module 50 as shown in FIG. 2, however, the size of a condenser 30 is reduced by the area of the second radiator 21 formed, thus making it difficult to expect a sufficient condensing efficiency and to ensure a sufficient amount of cooling water flowing in the second radiator 21.
On the other hand, FIG. 3 shows another example of the conventional cooling modules.
According to a cooling module 50 as shown in FIG. 3, the condenser 30, the second radiator 21 and the first radiator 11 are arranged in parallel to each other in an air flow direction. However, the heated air passing through the condenser 30 passes through the second radiator 21, thus giving a bad influence on the performance of the second radiator 21.
According to the load of the condenser 30, further, the air supplied to the second radiator 21 has a drastic temperature difference, thus making it hard to ensure the stable performance of the second radiator 21.
Therefore, there is a definite need to develop a new cooling module capable of ensuring good performance of a first radiator, a second radiator and a condenser, while achieving the miniaturization in size.